2015 STi Turbo Back Exhaust Options?

[CSF707]

I wanted to pursue another set other than Cobb and Invidia. I'm quite fond of the ARK GRiP sound but its just a cat back, though its much louder than the invidia q300 turbo back imo. If not maybe I can settle being stage 1 while being under warranty. There was a few cat backs that did sound nice.

As crazy priced these things are, one would think it be complete with all the piping

 

[IGOTASTi]

Our HKS Carbon-Ti Exhaust wasn't cheap, but was a complete system.

 

[CSF707]

I'm guessing most peeps grab a cat back they like and then add the Cobb down pipe? $$$$ lols

Just tryin to plan out what to do to the STi when I decide to pull the trigger on the pre order here in about 3 weeks.

 

[Batmobile_Engage]

If you have the money, I always say the best thing is to buy a full turbo-back exhaust from the same manufacturer because fitment is almost always better than a pieced together system.

The most important consideration should be the downpipe. For efficiency's sake, you want a full 3" downpipe that does NOT have any section that tapers to 2.5" (during a bend for example).

It's always a huge help in the future, if the downpipe you choose has an additional 1/4" NPT bung welded into the pipe for the adding a wideband O2 sensor.

Some people also look for a "partially divorced wastegate" downpipe. This downpipe will have a separator in the bellmouth end, that divides the exhaust gases exiting the turbine and the wastegate port. Some of these downpipes will often have a runner that reintroduces the wastegate gases to the main flow, a foot or two downstream. This reduces turbulence in
the bellmouth of the downpipe and which improves turbine efficiency.

Here's a couple visual examples...

 

[CSF707]

Ah oops, I keep forgetting some also sold it separately. Was the Invidia piping size correct all the way down, it appears to be? I was quite pleased with the products that I did get for two cars, one being a 11 STi.
Speaking of ARK though, they don't have that full down pipe from the motor it would seem? iduno, learning as I go

But when the time comes, I do want to have those 1/4 bungs so I can get that proper tune. Is the AEM wideband still considered the best out there or is there others now? I personally used prosport, but I think I saw where only certain tuning programs only worked on some like the AEM one.

Also is this normally a thing you have a shop install the down pipe before a tune or slap stage 2 tune and drive it there for a protune? Just wondering peoples thoughts on this.

Thanks

 

[Batmobile_Engage]

If you have a way to flash an off the shelf Stage II tune, you can swap in the downpipe yourself. If your tuner is close and you have the will power to stay out of boost, you could limp it there after the downpipe swap on the factory tune, but that's not highly recommended. If the downpipe already has the bung welded in, you should be able to drill/punch it out (be careful not to damage the threads) and install the wideband O2 sensor yourself. Personally, if I were you and the tuner was close, I would save myself some money and perform the work at home...and drive like grandma to the tuner.

Idk what you mean by "Speaking of ARK though, they don't have that full down pipe from the motor it would seem? iduno, learning as I go ". I don't know the newer STi models like some of you guys do, seeing how I have an '04. On the GD chassis (02-07) The post turbo exhaust generally consists of three pieces...downpipe, midpipe and axle-back/muffler section.

Idk that much about wideband 02 sensor options. I have an AEM UEGO that I have yet to use. Most people recommended that one and I got a good deal on it.